From 8c9fdd3ed1e7be91b936363fcacb2f8463a33b9a Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Thu, 25 Aug 2011 09:46:23 +1000 Subject: [PATCH] update_ts_time_stat currently updates idle time even if we are in iowait loop at the moment. The only real users of the idle counter (via get_cpu_idle_time_us) are CPU governors and they expect to get cumulative time for both idle and iowait times. The value (idle_sleeptime) is also printed to userspace by print_cpu but it prints both idle and iowait times so the idle part is misleading. Let's clean this up and fix update_ts_time_stat to account both counters properly and update consumers of idle to consider iowait time as well. If we do this we might use get_cpu_{idle,iowait}_time_us from other contexts as well and we will get expected values. Signed-off-by: Michal Hocko Cc: Dave Jones Cc: Arnd Bergmann Cc: Thomas Gleixner Cc: Alexey Dobriyan Signed-off-by: Andrew Morton --- drivers/cpufreq/cpufreq_conservative.c | 4 +++- drivers/cpufreq/cpufreq_ondemand.c | 4 +++- kernel/time/tick-sched.c | 8 ++++---- 3 files changed, 10 insertions(+), 6 deletions(-) diff --git a/drivers/cpufreq/cpufreq_conservative.c b/drivers/cpufreq/cpufreq_conservative.c index 33b56e5c5c14..c97b468ee9f7 100644 --- a/drivers/cpufreq/cpufreq_conservative.c +++ b/drivers/cpufreq/cpufreq_conservative.c @@ -120,10 +120,12 @@ static inline cputime64_t get_cpu_idle_time_jiffy(unsigned int cpu, static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall) { - u64 idle_time = get_cpu_idle_time_us(cpu, wall); + u64 idle_time = get_cpu_idle_time_us(cpu, NULL); if (idle_time == -1ULL) return get_cpu_idle_time_jiffy(cpu, wall); + else + idle_time += get_cpu_iowait_time_us(cpu, wall); return idle_time; } diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c index 629b3ec698e2..fa8af4ebb1d6 100644 --- a/drivers/cpufreq/cpufreq_ondemand.c +++ b/drivers/cpufreq/cpufreq_ondemand.c @@ -144,10 +144,12 @@ static inline cputime64_t get_cpu_idle_time_jiffy(unsigned int cpu, static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall) { - u64 idle_time = get_cpu_idle_time_us(cpu, wall); + u64 idle_time = get_cpu_idle_time_us(cpu, NULL); if (idle_time == -1ULL) return get_cpu_idle_time_jiffy(cpu, wall); + else + idle_time += get_cpu_iowait_time_us(cpu, wall); return idle_time; } diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index eb98e55196b9..f3409be12bed 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -158,9 +158,10 @@ update_ts_time_stats(int cpu, struct tick_sched *ts, ktime_t now, u64 *last_upda if (ts->idle_active) { delta = ktime_sub(now, ts->idle_entrytime); - ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta); if (nr_iowait_cpu(cpu) > 0) ts->iowait_sleeptime = ktime_add(ts->iowait_sleeptime, delta); + else + ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta); ts->idle_entrytime = now; } @@ -199,8 +200,7 @@ static ktime_t tick_nohz_start_idle(int cpu, struct tick_sched *ts) * @last_update_time: variable to store update time in * * Return the cummulative idle time (since boot) for a given - * CPU, in microseconds. The idle time returned includes - * the iowait time (unlike what "top" and co report). + * CPU, in microseconds. * * This time is measured via accounting rather than sampling, * and is as accurate as ktime_get() is. @@ -220,7 +220,7 @@ u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time) } EXPORT_SYMBOL_GPL(get_cpu_idle_time_us); -/* +/** * get_cpu_iowait_time_us - get the total iowait time of a cpu * @cpu: CPU number to query * @last_update_time: variable to store update time in -- 2.39.5